NEW YORK --- The oldest baby boomers are turning 62 this year, and some are using that as the catalyst to consider retiring.

It's possible because they can begin collecting Social Security benefits at that age, though at a lower level than if they wait until their full retirement age of 66 or older.

But baby boomers need to think long and hard about whether they're ready financially and psychologically to move into the next phase of their lives, experts say.

"For some, turning 62 is the siren calling from the shore," said William O. Wright, a certified financial planner in Wichita and president of the Financial Planning Association of Kansas. "There's the opportunity for the Social Security check ... and we've been through four years of bull market, so people have amassed the assets."

But boomers also need some sense of what they're going to do with their time.

"There's a set of financial conditions and psychological and qualitative conditions," Mr. Wright said. "Not having both can spell peril for the retiree."

Bill Frisbie, 64, who retired from his job selling print products 2 1/2 years ago because of Parkinson's disease, said he would have continued to work if he hadn't gotten sick.

"I liked the thrill of the hunt," he said. "I worked 60-hour, 70-hour weeks. I actually miss that."

He worries that if his wife, Lynette, 57, retires too early, she'll be bored or risk outliving their savings.

On the other hand, he said, the couple have been working with Mr. Wright to determine if they have the resources for her to join him in retirement in a couple of years.

"It would give us more time together," Mr. Frisbie said.

Experts caution that while Americans can begin collecting Social Security at age 62, their monthly benefit check will be at least 25 percent smaller than it would be if they wait to full retirement age. The impact on benefits can be determined at the Social Security Web site, www.socialsecurity.gov. Search for the "retirement age calculator" and then click on "age 62 benefit" for the analysis.

Bryan D. Beatty, a fee-based asset manager in Vienna, Va., said that many would-be early retirees also overlook health care costs.

"A lot of people don't realize that Medicare doesn't kick in until age 65," he said.

Bridging the gap in coverage between 62 and 65 can be expensive, he said, especially for workers who don't have retiree health coverage.

Drew Denning, the vice president for the retiree services division at the Principal Financial Group in Des Moines, Iowa, said boomers also need to "make sure your nest egg is at critical mass."

He noted that studies by the nonprofit Employee Benefit Research Institute in Washington, D.C., and other groups have found that a majority of Americans haven't saved enough and haven't tried to estimate retirement expenses.